The buckle having the above mentioned characteristics has been described in DE 102 59 115 A1. Insofar as the buckle that is installed in a motor vehicle causes rattling noise by hitting other installations of the motor vehicle, it is proposed to prevent and/or attenuate said rattling noise by applying a damping layer to the outside of the casing. Insofar as foam material is proposed as a damping material, the production of the casing cap forming the casing is addressed by means of insert-molding (in particular by means of two-component insert molding) in a single operation.